Salmon climbing a staircase, a hidden Japanese garden in Rainier Beach, and 50 pinball machines on free play.
Ballard Locks fish ladder
Free. Grounds 7am-9pm, the underwater fish-ladder window 7am-8:45pm. Watch boats change altitude and salmon climb stairs.
Kubota Garden
9817 55th Ave S: 20 acres of Japanese garden in Rainier Beach, free, sunrise to sundown. Far south of downtown, so drive or bus it.
Seattle Pinball Museum
508 Maynard Ave S in the CID: $25 adults buys unlimited play on 50+ machines from the 1960s on. Not a museum, an all-you-can-play.
Olympic Sculpture Park
2901 Western Ave, free and open 365 days, half an hour either side of sunrise and sunset. Calder's red Eagle against the Sound.
Museum of Flight
9404 E Marginal Way S, daily 10am-5pm, free parking. Huge air and space collection; the Space Shuttle Trainer tour books separately.